Methane leak blamed for Pemex headquarters explosion

MEXICO CITY -- An accumulation of methane gas was to blame for the Jan. 31 explosion that killed 37 people and injured 100 others at the headquarters of state oil company Petróleos Mexicanos, Mexico's attorney general says.

No traces of explosives were found at the scene in the Mexican capital, Jesús Murillo Karam told journalists at a late-night news conference Feb. 4.

According to the official, experts, including several from the United States and Europe, believe a spark detonated the leaking gas in a basement at one of the complex's several multi-story buildings. The gas may have seeped into the structure from subterranean ducts or from the sewers, he said.

Many Mexicans, including one prominent newspaper commentator, had speculated a bomb triggered the blast, which caused the collapse of several lower floors in the B-2 building, burying most of the victims. But Murillo said an exploding bomb would have left a crater and none was found. It also would have started a fire but there were no flames, he said.

The complex's 11,000 employees were told to return to work on Feb. 6. Most are employed in the facility's adjoining 53-story Pemex Tower, the city's second tallest building, which suffered only superficial damage.

The president of Mexico's largest plastic bag-making organization said he did not expect supplies of low density polyethylene from Pemex to be interrupted by the tragedy.

"We know the government is taking measures to ensure supplies are unaffected," Juan Antonio Hernández, president of Industriales de Bolsas Plásticas de México AC (Inboplast), a 40-strong group of plastic bag firms, told Plastics News.

Pemex is a major supplier of low density PE in Mexico while most high density PE is imported, according to national plastics industry association Anipac (Asociación Nacional de Industrias del Plástico AC).

Hernández, who is also the managing director of Falcon Plastics de México SA de CV, of Morelia, capital of the state of Michoacan, said: "I'm a mechanical engineer and was struck by the fact that after the explosion there was a flash but no smoke, which you would expect with a bomb."